Apparatus for expanding tubes



April 10, 1945.

H. BOYLES ET AL APPARATUS FOR EXPANDING TUBES Original Filed Feb. 8,1940 3 Sheets-Sheet l NEW %A @m \k INVENTOR I MT Mmw M April 1945. H.BOYLES ET AL APPARATUS FOR EXPANDING TUBES Original Filed Feb. 8, 1940 3Sheets-Sheet 2 April 10, 1945. H. BOYLES ET AL 2,373,097

' APPARATUS FOR EXPANDING TUBES Original Filed Feb. 8 1940 3Sheets-Sheet 3 EEEEEEEEEEEE INVEINTOR Patented Apr. 10, 1945 APPARATUSFOR EXPANDING TUBES Harry .Boyles and Raymond Walter Grabb, Jeannette,Pa., assignora to Elliott Company, Pittsburgh, Pa., a corporation oiPennsylvania Original application February 8, 1940, Serial No.

Divided and this application Septem-,

ber 11, 1941, Serial No. 410,416

9 -Claims.

Thi invention pertains to apparatus for expanding tubes, andparticularly, for expanding heat exchange tubes such as employed in acondenser, boiler, or feed water heater.

This application is a division or our copending application Serial No.317,876, filed February 8, 1940, entitled Method and apparatus forexpanding tubes."

In the manufacture of boilers, condensers, and similar apparatus,tubular heat exchange members are mounted in suitable tube sheets orbaffies that support or hold them in position. The tube sheet or baflleis holed-out to provide openings to receive the tubular members. Thetubular members are inserted in or through such holes and their wallportions expanded to press them tightly against the bounding edges ofthe holes provided. After the tube have been mounted within th holes inthe tube sheets. their edge portions are rolled in.

Particularly due to the temperature changes and conditions to whichapparatus of this type is subjected, considerable difllculty has arisenin providing a suitable type of connection or mounting constructionbetween the tube sheets and the heat exchange tubes. In the first place,it is customary, and in many cases advisable, to provide sheets of onetype of metal and tubes of to the high temperature conditions involved.For example, aflexible packing has a tendency to leak and its life islimited.

In view of conditions such as above outlined. we have endeavored todevelop a new method of attack which will meet the problems presented.In our development, heavy tube sheets are employed and an initial bow imade in the tubes so that there is a slight are along the tube length.As expansion occurs, the tub length may vary with the curvature of thearc. The present invention deals particularly with procedure andapparatus for enabling a new and improved utilization of such aconstruction.

It will be noted that a small amount or expansion may produce a greatchange in curvature, and that a very moderate change in temperature mayproduce a very great change in tube deflection. In longer tubes, it isdifllcult to initially secure straightness of the tube, and to hold theinitial deflection due to weight in the same direction. Consequently,with varying temperatures the deflection of the tubes is not onlyvariable in amount, but differs in direction. We

25 have also found it advisable to provide a tube another type. Forexample, the heat exchanger shells may be of iron, while the tubularsurfaces of some suitable material such a an alloy of copper.Consequently, due to the different coefllcients of expansion, the tubeswill expand more than the shell when the condenser is heated up. In someheat exchange apparatus, the exterior of the condenser may be lessseverely heated than the interior portions and the shell and the tubesmay have difierent thicknesses, all or which contribute to the differentcoeflicients of expansion and to differences in temperature between theshells or sheets and the tubes, themselves.

As a result of the different temperature condition and differentcoefficients of expansion as above outlined, the tube may break awayfrom their mounted relationship with respect to the shells and viceversa, as many tons of pressure may be exerted between such portions ofthe apparatus. Some have attempted to alleviate these conditions byproviding a form of flexible packing for the tubes or by making theentire tube sheet in which one endof all the tube is mounted subject tomovement in 'a' floating head. It will be apparent that such methodshave their difllculties and limiting features, particularly due 56construction that will not fail due to the stresses and strains involvedeven it the apparatus is overloaded beyond its normal capacity for aperiod of time; this will give the vent or other safety devices fullopportunity to operate.

If'the apparatus such as a condenser or heater is rolled with the tubesheated, the differential expansion upon cooling puts the tubes under apartial tension, at least in theory. If the tension becomes heavyenough, the tubes may elongate within their elastic limits due to thestresses imposed. We have found the structure i more flexible with thetubes in'tension as water boxes normally are of heavy section of castiron or welded steel to provide corrosion-resistance. -Such boxes tendto prevent the tube sheets from expanding outwardly and hold them inplace more positively than it the tube sheets are pulled inwardly bycontracting tubes. It is also apparent that due to differences intemperature between the top and bottom of the apparatus and other partsthereof, some of the tubes may be under tension and others undercompression. In accordance with this method, both tube ends were rolledin the tube sheet and the tube sheets were fixed slightly further apartin position than they would normally be it the tube sheets were to bepositively held in position.

In rolling the tubes, holes in the tube sheet were drilled out and thenreamed to a controlled size. The tube, itself, is manufactured with apredetermined diameter and within a closely held tolerance. As the tubematerials are somewhat ductile, the wall portions were expanded by atool inserted in the interior of the tube and revolved. This tool rolledthe tube metal to a larger diameter-until tight contact was made betweenthe tube exterior wall and the inner edges of the hole in the tubesheet. In order to insure suitable contact and provide holding power, itwas found necessary to continue the expansion,

the equivalent of several thousandths of an inch on a one inch diameterof the tube, for example. beyond the point where actual contact wasmade, in order to provide a mechanical and continuous contact betweensuch surfaces. This last operation after contact was made tends toextrude metal of the tube and heavy pressures and plastic flow of thetube material results.

In carrying out the operation, it is obviously necessary to havetheworkmen on the outer side of the tube sheet away from the tubes.Heretofore, it has been the customary practice in the art to extrude thetubular wall towards the spacing between tube sheets or towards theinterior of the condenser or away from the open end through which thetool was inserted. This extrusion, even when a few thousandths of aninch, was significant enough to produce a, considerable change in thedeflection of the tube.

We have been able to meet the problems involved in this type ofoperation as well as in the general operation of securing or mounting atubular member in tube sheets, by certain new and improved operativemethods. In this connection, we prefer to extrude the metal, if the tubeis to be rolled from the inside, towards the operator and to avoidsuperimposing the extruded portion upon the tube to, in efiect, stretchthat it may be inserted and withdrawn from the tube; previousconstructions had a tendency to anchor about the point at which theyfirst came into contact with the inner wall of the tube and to extrudeaway from this point.

In accordance with the present invention, we determined the advisabilityof beginning the tube rolling or expanding operation at a portion of thetube farthest from the end which is to be mounted, or in other words,farthest removed from the operator, and to cause the extrusion to takeplace in direction towards the end of the tube that is to be mounted andthus towards the operator. We have also been able to develop a tool thatwill eflect such a result in an improved manner.

Although as above intimated, our invention has particular value inexpanding heat exchange tubes for suitably mounting them in tube sheetsor header constructions, it-wiil be apparent that the presentinvention'may also be applied with eflicacy in other cases where walledmembers are to be expanded outwardly.

Thus, itlias been an object of our invention to provide asolution to theproblems encountered in suitably mounting tube members in their headersheets. i

Another object of our invention has been to provide new and improvedprocedure and apparatus for suitably securing or mounting tubularmembers in tube sheet members, particularly adjacent end portionsthereofr A further object has been to expandor extrude walled members ina new and improved manner.

A still further object has been to provide a new and improved type ofmounting construction for tubular members such as employed in heatexchangers, condensers, and the like.

These and many other objects of our invention will appear to thoseskilled in the art from I the drawings, the description thereof, and theappended claims.

In carrying out our invention, we preferably insert a suitablemandrel-like roller device into the end of a tube and then actuate thedevice in such a manner as to begin the rolling operation at the far endof the device and to move it, while increasing the expanding pressure,in a direction towards the operator, or in other words, towards the endof the tube through which the tool has been inserted. After thispreliminary operation, we preferably automatically change the angle(decrease the angle of application) of the device to roll the inside ofthe tube substantially parallel, and finally, to provide a, gradually orsmoothly tapered transition between the balance of the tube and theportion which has been expanded, all with a minimum of stress and strainupon the tube and without leaving sharp areas or rings and withoutoverstressingany portion of the inside of the tube.

Previously, apparatus of this type produced a sharp thin edge at thepoint where the rolling was the ultimate collapse of the tube at such apoint.

The tool is also employed in such a manner that the extent of each stepof the rolling or extruding operation is automatically controlled andsuch that it automatically releases itself upon completion of the work,permitting its removal by the operator, all without damaging the qualityof the tube and additionally producing an improved outer surface fromthe standpoint of holding the tub; in position with respect to its tubesheet.

The drawings show a preferred apparatus embodiment of the presentinvention:

Figure 1 is a longitudinal side view in elevation of apparatus forexpanding tubular members in accordance with our invention;

Figure 2 is a longitudinal view in side section through a toolconstructed in accordance with our invention and shown in Figure 1; inthis view, the device is shown in an initial or starting position withrespect to a tubular member A that is to be expanded in a tube sheet B;

Figure 3 is a vertical longitudinal section of theapparatus of Figure 2,but showing it in a final position after it has completed the expandingoperation and is ready for removal from the tube member; A

Figure 4 is a front section taken along the line IV--IV of Figure 2;

Figures 5 and 6 are transverse sectional views taken along the lines V-Vand VI-VI of Figures 2 and 3, respectively.

Figure 7 is a side sectional view of a clutch sleeve of the apparatusshown, for example, in Figure 2; Figure 8 is an exploded sectional viewof amok-like clutch jaws and their associated P 2 Figures 9, 10, and 11are sectional views of other details of the apparatus of Figure 2;

Figures 12, 13, and 14 are all longitudinal sectional fragments of theexpander portion of the apparatus shown in Figures 2 and 3, in differentpositions; in Figure 12, the apparatus is near the end of its so-calledinner extruding operation; in Figure 13, it has finished the innerextruding operation and is rolling a substantially parallel surface; andin Figure 14, the rolling operation has been completed, and theapparatus automatically released from rolling contact with the innerwall portions of the tubular member A; the position of Figure 14 is alsothe position of Figure 3;

Figures 15, 16, and 17 are cross-sectional views taken along the linesXV-XV, XVI-XVI, and XVII-XVII of Figures 12, 13, and 14, respectively;

Figure 18 is a longitudinal sectional view showing the yoke orclevis-like nature of the mount structure illustrated in Figure 8 andtaken at 90 with respect thereto;

Figure 19 is a partial sectional detail showing the two dovetailed tangson the end of the sleeve shown in Figure and taken at 90 with respectthereto. As shown, for example, in Figure l, the device of the presentinvention includes an operating shaft 2| that at one end hasmandrel-like portions a, b, and c, that are operatively engaged by atube-expanding unit 30. The shaft 2| also has a threaded portion 23operalbly mounted within a clutch unit 20 and terminating at one end ina connecting shank portion 22. The device may thus be rotated by a motorl0 through a shaft i I and connector I2.

In using the device, the operator grips sleeve 50 of clutch unit 20,retains the clutch in a released position (see Figure 3), and insertsthe tool in the tube A in a position for rolling. The operator thenpushes or slides the threaded portions 23 to their extreme forwardrelationship with respect to the clutch 20; sleeve 50 is moved forwardlywith respect to part 65 (from the position shown in Figure 3 to thatshown in Figure 2, for example) to engage the clutch (see Figure 2). Themotor I0 then rotates the entire device including the unit 20 within thehands of the operator. During such rotation the mandrel portions a, band 0 move backwardly and effect the desired expanding or swagingoperation through rollers 3| of the roller or case expanding unitbackwardly and automatically advancing the various steps of theexpanding o ration until the operation has been completed and theapparatus has been moved to the position shown in Figures 3 and 14. 1

Referring particularly to Figures 1, 2, and 3, the object of the taperedends of rolls 3| is to blend the large rolled diameter of the tube A tothe small'unrolled diameter of the tube to avoid sharp shoulders that,in turn, produce eddy currents in the liquid stream. ,The roller cage isprovided with openings adapted to receive rollers 3| whose front endsare somewhat beveled to correspond to the forward bevel of the cage 3|).As will be noted, the cage 30 is inwardly drilled out to receive themandrel portions of the shaft 2| and to permit the rollers 3| tosuitably operaibly engage between the mandrel porfemale slide portionadapted to removably receive a complementary male slide or stud portion4|, see Figures 1 and 10, of a mandrel shaft enclosing tube 40. That is,the portions 35 and 4|, are, in effect, slidably and removablydovetailed. The dovetailed connection serves bgth as a key to cause theconnected parts to rotate and as a detachable coupling. It is desirableto separate the two members and 34 to substitute one cage for anotherwhen the tool is to be used upon a tube of a diiierent diameter or whereit is necessary to substitute one cage for another. Separation may beeffected by unscrewing tube All from the member 50 and then sliding thecage and tube together off the innermost end of the mandrel, after whichone member may be moved transversely with respect to the other todisemgage the dovetailed parts. The base it has a forward ledge portionfor receiving a sleeve-like stop element 3? thereover. As will be noted,this sleeve-like element is held in position by a circular lock spring36 having an inwardly depending finger $10. that engages an annulargroove 38 of the base member 34. The sleeve stop 31 is provided with anofiset inner front edge portion 39 for receiving an end of the tube A tobe expanded and for thus governing the distance the tool is insertedwithin the tube. This sleeve-like stop 51 being removable, may beinterchanged with other stops having different depth of ledge portions39 as desired, depending upon the desired depth of insertion of the toolwithin the tube A.

The clutch member 20 comprises an outer sleeve member 50 having a pairof inwardly-offset annulus-like portions d and e. A pair of chuck-likeJaws or followerelements 56 are slidably positioned within bifurcatedend portions of a mount element 52, see Figure 8. The clutch mountelement 52 has a portion 53 threaded to receive and be secured to a likethreaded portion 42 of the mandrel shaft enclosing sleeve 40.

The elements 52 and 56, shown particularly in Figures 2, 3, 5, 6,, '7,and 8, are operably mounted within the clutch sleeve 5|] and are held inposition by a removable cap 65, see Figure 4, that has a flange portionengaging offset portion h and i of the elements 52 and 55, respectively.The cap 55, itself, is removably held in position by set screws 66. p

As shown, for example, in Figures 8 and 9, each of the threadedfollowers or chucks 56 is provided with a shoe 58 removably mounted asshown by a set screw 59. Each shoe 58 is beveled as shown and extendsover upon one offset ledge por. tion of the bifurcated core or mountelement 52.

A pair of follower-positioning pins 60 slidably extend through holes 55,see Figure 5, 6, and 8, and in the core element 52 and have a flatsurface that contacts the lower surface portion of the shoes 58. Theother end of each pin 60 is rounded off to engage, as shown in Figures 5and.

6, the inner wall portions of the sleeve 50. When the clutch sleeve 5|!is moved forwardly against a slip-sleeve stop 43 (see Figure 2),projecting ledge portions j and g of the screw followers 56 abut againstinwardly-extending ledge portions k and l of the sleeve 50, see Figures*2 and 3, holding or locking them against the threads 23 of the mandrelshaft 2|. At the same time, the pins .60 enter the offset portion d ofthe sleeve 50 and are released, permitting the above-explained followeror clutch engagement.

When the sleeve 50 is moved backwardly to the position shown, in Figure3, it will be noted that the ledge portions f and g of the followers 58enter the offset portions 1! and e of the sleeve 50, and that the pinelements "abut against the annular ledge l to effect an outwardseparation (spreading apart) of the followers II by pressing against andmoving the shoes 58 outwardly, see Figures 3 and 6.

As will appear, the stop 43 is adiustably mounted on themandrel-enclosing sleeve 40 by means of a set screw 44.

As will be noted particularly in Figures 1 and 2, the mandrel portionproper of the shaft 2| includes an outwardly beveled portion a, aparallel portion b, and a dropoif, or a portion of less diameter c.

As shown in Figure 12, the rolling expanding X operation upon the innerwall of tube A begins with the rollers 3| and at the inner or lesserdiameter beveled portion of mandred a, to effect an initial outwardexpansion, beginningat the forward end portions of the rollers 3|. Asthe portion a of the mandrel moves outwardly toward the open end of thetube with respect to the roller cage 3|) and associated rollers 3|, theexpanding operation is progressively effected as the diameter of thepart a increases toward the inner end of the mandrel. This causes thepart of the tube most remote from the operator to be first engaged andthe expanding operation then progresses outwardly toward the free end ofthe tube, tending to induce the flow of the metal of the tube toward itsfree end. When the cage 3| and its associated rollers engage the mandrelportion b, see Figure 13, the rollers 3| operate parallelly to even outthe previous extrusion and make the inner walls of the tube Asubstantially parallel, with a gradual bevel that marks a transitionpoint between the original surface of the tube and the portion thathas-been extruded. Later, when the cage 30 andits associated rollers 3|are engaged by the mandrel portion 0, such rollers move inwardly and arethus released. The result is that the tool speeds up and the operator iswarned that the operation has been completed and to withdraw the tool.

The outward feed of the mandrel shaft 2| relative to the roller cage 3|,is effected by the planetary action of the rollers 3| in contact withface, being stationary, the other, namely, the

mandrel surface, being rotated. The frictional contact is such that therollers 3| rotate with substantially the surface speed of the mandrel 2|and rotate upon the tubular wall A in such a manner that the cage 3|)revolves, as its diameter is less than the diameter of the tube wall.

Driving force is transmitted'from the mandrel 2| which is driven by themotor l through the tube rollers 3| and tube wall back to the rollercage 30, and from the roll cage 30, backward to the clutch unit 2|] andits controlling mechanism. As a result, a relative rotation is effectedbetween the clutch 20 which carries the female follower elements 56 andthe portion 23 of the mandrel which constitutes the" male element. Therolls 3|, themselves, determine the relative diiference in speed betweenthe mandrel 2| and the cage 30, and thus, between male and femaleportions 23 and ll of the clutch 20. This relative differ. ence inspeeds results in a progressive backward movement of the mandrel screw23 with reference to the clutch unit 20; and, this in turn, moves themandrel portions 0, b, and c progressively backwardly with respect tothe roller cage 30, forcing the rollers ll against the inner walls ofthe tube A in the manner previously outlined.

The entireapparatus can be readily dismounted and taken apart forreplacement and repair purposes or for adapting it to various sizes oftubes, etc. The clutch sleeve 50 is pulled backwardly over the cap 65,as shown in Figure 3, to effect a release of the clutch followers 66prior to inltiating the tube expanding operation, in order that thethreaded mandrel shaft 2| may be pushed forwardly to its extreme forwardposition as shown in Figure 2 before inserting the roller cage 30 withinthe tube A. At the time of insertion of the roller cage, the sleeve 50is moved forwardly as shown in Figure 2, or to the position shown infull lines in Figure 1 (the previous position being shown in dottedlines in the same figure), to in effect, lock the female clutch followerportions 56 in threaded engagement with the male screw portion 23 of themandrel shaft 2|, and to initiate when actuated by the motor ID, theprogressive expanding action previously explained.

Expanding the tube A'outwardly towards its ends in mounting it withintube sheets B also prevents buckling as the force. is applied away fromthe center of the tubing.

As will appear to those skilled in the art, the procedure of the presentinvention may be accomplished by other suitable apparatus, and thepresent preferred apparatus construction may be modified and suitablesubtractions, additions, etc.. thereof may be made without departingfrom the spirit and scope of the invention as indicated by the appendedclaims.

We claim:

1. A tube expander of the class described comprising a mandrel having aninner end adapted to be entered into a tube and having an outer endadapted to be engaged by actuating means, the inner end portion of themandrel having a cylindrical section of small diameter at the innermostend thereof, there being a cylindrical section of larger diameter nextto said section of smaller diameter, there being also a conical sectionof the mandrel tapering from the said larger cylindrical section in adirection which diminisnes toward the outer end of the mandrel, a cagearound the inner end portion of the mandrel having a plurality ofradially movable rollers therein which rest on the periphery of themandrel, the said rollers also having a cylindrical section and aconicalsection, the cylindrical section of the rollers being positionedat the beginnin of the tube-expanding operation, adjacent to the conicalsection of the mandrel, at which time the conical section of each of therollers is positioned adjacent to the cylindrical section of themandrel, the mandrel being longitudinally movable relative to the cageto present the periphery of any of said three sections for engagement bythe rollers, means for rotating the mandrel, and means for moving themandrel outwardly with respect to the tube in which it is entered andwith respect to the cage to smcessively engage said rollers by the conesection, the section of larger diameter, and the section of smallerdiameter, in the order named, to exward the free end of the tube, thesaid section of smaller diameter enabling the rollers to move inwardlyto release the tool after the portion of the larger diameter has passedthrough the rollers.

2. A tube expander of the class described comprising a mandrel having aninner end adapted to be entered into a tube and having an outer endadapted to be engaged by actuating means, the inner end portion of themandrel having a cylindrical section of small diameter at the innermostend thereof, there being a cylindrical section of larger diameter nextto said section of smaller diameter, there being also a conical sectionof the mandrel tapering from the said larger cylindrical section in adirection which diminishes toward the outer end ofthe mandrel,

a cage around the inner end portion of the mandrel having a plurality ofradially movable rollers therein which rest on the periphery of themandrel, the said rollers also having a cylindrical section and aconical section, the cylindrical section of the rollers being positionedat the beginning of the tube expanding operation, adjacent to theconical section of the mandrel, at which time the conical section of therollers is positioned adjacent to the cylindrical section of themandrel, the mandrel being longitudinally movable relative to the cageto present the periphery of any of said three sections for engagement bythe rollers, means for rotating the mandrel, and means for moving themandrel outwardly with respect to the'tube in which it is entered andwith respect to the cage to successively engage said rollers by the conesection, the section of larger diameter, and the section of smallerdiameter, in the order named. to expand the inside of the tube andinduce the resulting flow of metal in the tube outwardly toward the freeend of the tube, the said section of smaller diameter enabling therollers to move inwardly to release the tool after the portion of largerdiameter has passed through the rollers, the said rollers having conicalterminal portions directed toward the inner end of the mandrel diametertoward the inner terminal of the mandrel, a cage through which themandrel passes, said cage having radially movable rollers therein, thesaid rollers also having a cylindrical section and a conical section,the cylindrical section of the rollers being positioned at the beginningof the tube-expanding operation adjacent to the conical section of themandrel, at which time the conical section of each of the rollers ispositioned adjacent to the cylindrical section or the mandrel, means forrotating the mandrel and imparting a planetary, movement to said cage,and means on the outer end portion of the mandrel utilizing theplanetary motion of the cage for efi'ecting endwise travel of themandrel relative to the cage and proportionately to the speed ofrotation of the cage.

4. A tube expander of the class described comprising a mandrel having aninner end portion adapted to be entered into a tube and an outer endportion, the inner end portion having a tapered a cage surrounding saidinner end portion of the mandrel, said cage having a plurality ofradially movable rollers therein which engage the periphery of saidmandrel, and also engage the inner,

wall of the tube to be expanded, means for rotating the mandrel,rotation of the mandrel imparting planetary rotation to the rollersengaging the mandrelxthe resulting rotation of the rollers setting upplanetary rotation of the cage at a speed slower than the rotation ofthe mandrel, the outer end of said mandrel having a threaded sectionthereon, and nut means on the threaded part of the mandrel connectedwith said cage whereby said nut means rotates in the same direction asthe mandrel but at a slower speed than the mandrel to effectlongitudinal movement of the mandrel through the cage.

5. A tube expander of the class described comprising a mandrel having aninner end portion adapted to be entered into a tube, and an outer endportion, the inner end portion having a tapered section thereon ofinwardly increasing diameter, a cage surrounding said inner end portionof the mandrel, said cage having a plurality oi radially movable rollerstherein which engage the periphery of said mandrel, and also engage theinner wall of the tube to be expanded, means for rotating the mandrel,rotation of the mandrel imparting planetary rotation to the rollersengaging the mandrel, the resulting rotation of the rollers setting upplanetary rotation of the cage at a speed slower than the rotation ofthe mandrel, the outer end of said mandrel having a threaded sectiontherein, and nut means on the threaded part of the mandrel connectedwith said cage whereby said nut means rotates in the same direction asthe mandrel but at a slower speed than the mandrel to effect thelongitudinal movement of the mandrel through the cage, and means fordisengaging the nut means from the mandrel to enable the mandrel to befreely moved in a longitudinal direction through the cage.

6. A tube expander of the class described comprising a mandrel having aninner end portion adapted to be entered into a tube, and an outer endportion, the inner end portion having a tapered section thereon ofinwardly increasing diameter, a cage surrounding said inner end portionof the mandrel, said cage having a plurality of radially movable rollerstherein which engage the periphery of said mandrel, and also engage theinner wall of the tube to be expanded, means for rotating the mandrel,the resulting rotation of the rollers setting up planetary rotation ofthe cage, the outer end of said mandrel having a threaded sectiontherein, and nut means on the threaded part of the mandrel connectedwith said cage whereby said nut means rotates in the same direction asthe mandrel but at a slower speed than the mandrel to effectlongitudinal movement of the mandrel through the cage, said nut meanshaving radially movable portions thereon for engagement with thethreaded mandrel, and manually operable means for selectively effectingradial movement of said sections to release or engage the threadedportion of the mandrel.

'1. A tube expanding tool of the class described comprising a mandrelhaving an inner end portion adapted to be entered into a tube to be ex-I panded, said inner end portion having sections of different diametersthere along, a cage through which the inner end of the mandrel extendslongitudinally an relative to which the mandrel is movable in alongitudinal direction, said cage havsection thereon of inwardlyincreasing diameter,

ing a plurality of radially movable rollers therein which bear againstthe periphery of the mandrel and which are adapted to bear against theinterior of the tube into which the cage is inserted. and adapted toimpart planetary rotation of the cage relative to the mandrel, therotation of the cage being at a slower speed than the rotation of themandrel, means for rotating the mandrel,

said mandrel having a section which is threaded, a sleeve surroundingthe threaded section 01 the mandrel, radially movable thread-engagingelements in the sleeve movable into and out 01' onerative engagementwith the threads on the mandrel, cooperating means on the sleeve andelements for eflecting the radial movement thereof, and means fortransmitting rotary motion between the thread-engaging elements in thesleeve and the cage, whereby the planetary movement of the cage causedby rotation of the mandrel effects a rotation of the thread-engagingelements relatively to the mandrel and in the same direction as themandrel, whereby, when the said thread-engaging elements are in positionto engage the threads on the mandrel, the mandrel will be movedlongitudinally through the cage and at a rate proportional to thediilerence in the speed of rotation of the cage and the speed ofrotation of the mandrel.

8. Apparatus for expanding the tube," having an open end, whichcomprises, in combination, a mandrel for insertion into the tube throughthe said open end, actuating means for the mandrel including means forretracting the mandrel through the said open end, and means for rotatingthe mandrel, a cluster of expanding rollers disposed around the saidmandrel for expanding a portion of the tube from a point remote from theopen end to the said open end, the said rollers being cylindricalthrough a portion thereof, the remaining portion of the rollers beingconical, the conical portion including the inner end of each roller, acomplementary configuration on the mandrel, the complementaryconfiguration of the mandrel being a tapered portion followed by acylindrical portion of a diameter equal to the largest diameter of thetapered portion, whereby longitudinal movement of the mandrel to thetube causes first an expanding action or the rollers on the tube toexpand the said portion of the tube and then to cause an automaticshifting of the rollers relative to the tube to roll the expandedportion 0! the tube substantially parallel interiorly. thereby providinga smoothly tapered transition between the expanded portion of the tubeand the remainder thereof, and means for retaining the rollersimposition on the surface of the tube.

9. Apparatus for expanding a tube having an open end, which comprises amandrel having an outer end and an inner end, the mandrel comprisingthree sections, which are, in order from the outer end; a conicalsection enlarging from,

the outer end of the mandrel towards the inner\ end thereof, a firstcylindrical section and a second cylindrical section, the firstcylindrical section abutting against the larger end or the conicalsection and having a diameter substantially equal to the diameter oi thesaid larger end or the conical section, the second cylindrical sec--tion of the mandrel being or relatively small diameter, a cage aroundthe mandrel, a plurality of radially movable rollers in the cage bearingon the periphery of the mandrel, the said rollers having a cylindricalsection and a conical section, the cylindrical section 0! the rollersbeing toward the outer end of the mandrel, and the conical section oi!the rollers being toward the inner end oi' the mandrel, and operatinginstrumentalities for the mandrel for rotating the mandrel in the tubeand for moving the mandrel longitudinally relative to the tube,operation or the mandrel during longitudinal movement thereof, causingthe rollers to expand the tube during an engagement of the conicalsection of the mandrel with the rollers, and then to shift the rollersrelative to the tube upon engaging the first cylindrical portion of themandrel incident to withdrawal of the mandrel, so that the expandedportion of the tube is rolled parallel interiorly to provide a smoothlytapered transition between the expanded portion 01' the tube and theremainder thereof.

HARRY BOYLES. RAYMOND WALTER GRABB.

